Over the years U-Haul, the do-it-yourself rental company, has never been shy about using its equipment as billboards to tout their features and how they benefit the customer. “Our low floors make your move easier,” reads one message on the rear door of trucks and trailers. “Low profile design, tow with any car, fuel efficient,” it says on the door of a light van trailer. 

“Trim Line Fuel Saver,” read the badges on the fenders of Ford E-series chassis with van bodies. U-Haul’s been claiming that for years, but I rented one in the early ‘90s and it got about 9 mpg. A few weeks ago I saw the latest version.

The truck is a “26-foot Supermover … with enhanced aerodynamics.”  Drawings depict air moving past the body’s rounded corners, and skirts under the cab and body. “Well, look at that,” I thought. The radius of some of its rear-facing corners seems a little short, but it beats squarish edges. Aerodynamicists will tell you that proper treatment at a vehicle’s rear can be more important than what’s up front. 

Corner radius is one of the things I wrote about many years ago when aerodynamics became important and topical. That was following the second Arab Oil Embargo of 1979. The ‘80s were a time of experimentation and innovation, and commercial trucks and trailers became smoother and got better fuel economy, at least while traveling at highway speeds.

As I recall, experts said a 6-inch corner radius was optimal for moving air around a truck or trailer body’s 90-degree front corner. Tests showed that smaller radii didn’t save as much fuel, but were worth something. The vertical front corners on U-Haul bodies, not just the ones on the Supermover, look to be about 6 inches, and that is a benefit to customers.

As you’d imagine, corner radii are set when the trailer or body is designed and built. It’s not practical to add them later. But in the 1980s and beyond, a number of add-on products went to market. Most were mounted on the roof of the cab and moved the passing air away from the large, flat nose at the body’s front. These were called “deflectors.”  

Some deflectors were mounted on the nose itself. One was the Nose Cone, a bubble-shaped product originating in the 1970s. I knew its inventor, Joe Fitzgerald, and his story is interesting (see www.nosecone.com). 

Anyway, U-Haul is now blowing its horn for something it seems to have been doing for quite a while, because older equipment has the rounded corners. The graphics on its new Supermover truck bodies are almost educational to people who seldom if ever think about air flow, which is probably most of them. I’d call that a public service.

Related: Well Thought-Out Details on U-Haul’s Trailers